[Dune] Problem with latest dune-common / strangy error message with quadmath.hh

[Simon Praetorius]

We changed one thing in cmake which might be related:

https://gitlab.dune-project.org/core/dune-common/-/merge_requests/1552

We removed extra compile definitions and options, since they are 
actually not needed if the GNU extensions of gcc are activated and they 
triggered other problems. Now, it could be that in MacOS things are 
different. This happened before since we do not test on a MacOS 
computers frequently.

The error message that you have posted is strange, though. There is no 
error in the code, except if something is defined/undefined by the 
preprocessor that we cannot see here. Have you tried adding the flag 
"-fext-numeric-literals" and maybe the preprocessor defintion 
"-D_GLIBCXX_USE_FLOAT128" manually?

Best,
Simon

Am 08.12.25 um 18:48 schrieb Benedikt Oswald:
>
> Dear Dune,
>
> using the latest dune git versions, I encounter this error:
>
> ----------------------
>
> /Users/oswald/gitwork-demokritos3d/demokritos3d/demokritos3d-dune-bleeding-edge/dune-common/dune/common/quadmath.hh: 
> At global scope:
> /Users/oswald/gitwork-demokritos3d/demokritos3d/demokritos3d-dune-bleeding-edge/dune-common/dune/common/quadmath.hh:318:21: 
> error: expected initializer before '&' token
>   318 |     inline Float128 fma(const Float128& t, const Float128& u, 
> const Float128& v)
> --------------
>
>
> Now, I have another code which uses quadrature & compiles well & even 
> links, which rather suggests this is my fault.
>
>
> I use:
>
> Mac OS X, 15.7.1 (24G231)
>
> gcc 15.1
>
> and this gcc flag: -fext-numeric-literals
>
>
> But still, if you have a suggestion, I am grateful,
>
> thanks & greetings, Benedikt
>
>
>
>
>             LSPR AG
>             Dr. sc. techn. Benedikt Oswald
>             Founder, CTO
>             
Kriesbachstrasse 3b
>             CH 8304 Wallisellen
>             
+41 43 366 90 74
>             benedikt.oswald at lspr.swiss
>             www.lspr.swiss <https://lspr.swiss>
>
>
>
>
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-- 
Dr. Simon Praetorius
Technische Universität Dresden
Fakultät Mathematik
Institut für Wissenschaftliches Rechnen
Tel: TUD-34432
Web: tu-dresden.de/Members/simon.praetorius

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